NOCTI Electrical Practice Test

These questions are part of the practice quiz. Start practicing

• How many current-carrying conductors are needed between two three-way switches?
• What is the purpose of a voltage regulator in a power supply, and what happens if it fails?
• In box fill considerations, do internal clamps contribute to the required box volume?
• Which statement best describes Kirchhoff's Current Law?
• Scaffolding serves primarily as what?
• Define 'ground fault circuit interrupter' and its typical location requirements.
• In a long feeder with significant impedance, the load-end voltage under full load is typically:
• What is a common symptom of incorrect traveler wiring in a three-way switch system?
• In three-way switch installations, the traveler wires provide what function?
• If a polarity tester indicates reverse polarity on a receptacle, which wires are reversed?
• A 230 V single-phase motor has a full-load current of 5 A. Its locked-rotor (starting) current is 6 times FLC. What is the starting current?
• In a DC circuit with a 120 V source connected to a 40 Ω resistor, calculate the current and the power dissipated by the resistor.
• What is a key advantage of using a clamp-on meter for current measurement?
• A luminaire is another term for which component?
• In walls or ceilings of combustible material, the box set back from the finished surface must be ____ inch.
• Describe a typical timer (T1) control function in a lighting circuit.
• Which steps would you take to verify a miswired 120/240 V circuit between two receptacles and a panel?
• Which statement best describes an IC-rated luminaire?
• Which organization publishes the NEC?
• What is the typical interpretation of the first two bands and the third band in the 4-3-2 resistor color code?
• What is the general purpose of a motor contactor in a control circuit?
• Explain how a wiring diagram helps an electrician during installation.
• Arc is defined as the flow of a high amount of current across an insulating medium, like air.
• A limit switch configuration that is closed in its normal state is described as which type?
• On a polarized receptacle, which slot identifies the hot side?
• What is considered the most important safeguard against serious or fatal accidents?
• What two primary categories are used to classify electrical hazards in arc flash analysis?
• The grounding prong on a three-prong plug is optional and may be removed.
• How would you calculate the approximate voltage rise along a long feeder due to insufficient regulation?
• Which factor increases box fill when counting devices inside a box?
• Which table in the NEC pertains to wire ampacity?
• In an electrical system, what is the difference between neutral and ground, and what is the typical voltage difference between them during normal operation?
• How long does a load have to be on, to be considered continuous load?
• Which term describes a device used to provide temporary access to elevated work areas during electrical maintenance?
• Which of the following conductors can be connected to a lug that is listed for CU only?
• What is the effect of device yokes on box fill?
• What is the minimum spacing required between two ground rods?
• What is the difference between a feed and a branch circuit in a typical electrical system?
• Ampere is the unit of measure for electrical current.
• A device is labeled 15 A at 125 V. What is the maximum current it should safely carry before tripping or overheating?
• Which statement best describes how to tighten a NM cable connector?
• A limit switch that is normally opened is open when in its default state. Which option correctly describes this?
• Which federal agency enforces workplace safety rules?
• What is the proper sequence of steps for a safe lockout/tagout procedure?
• The maximum allowable weight of a fixture directly attached to an outlet is ____ pounds.
• What is the unit of measure for voltage?
• Explain the difference between a 'pigtail' and an incoming conductor in a box, and why pigtails are used.
• Which NEC concept governs how to size an overcurrent protection device for a given circuit, and what is the general rule for continuous loads?
• ARC fault circuit interrupters are required in the ______.
• A service calculated at 25 A; what is a reasonable suggestion for the minimum OCPD size considering 125% rule for continuous loading?
• In walls or ceilings of combustible material, what is the required box set back from the finished surface?
• Which of the following is the maximum allowable weight of a fixture directly attached to an outlet?
• What indicates a properly functioning circuit breaker?
• What is conductor ampacity, and what factors can cause derating?
• Which type of extinguisher should not be used on electrical fires?
• Finish wiring is commonly referred to as what?
• Which code article governs definitions used for interpreting terms?
• Which statement best describes the two concepts of grounding and bonding?
• A 120 V branch circuit has a 134 ft length and feeds a load drawing 25 A. Using a copper conductor with 2.5 mm^2 cross-section (approx. resistance ≈ 0.007 Ω/m), calculate the approximate voltage drop (round-trips length = 81.6 m).
• Grounding is an electrical connection to ground (the earth).
• A polarized plug is designed to differentiate between which conductors and will fit into a receptacle only one way.
• What device automatically energizes a lighting circuit?
• What is the practical difference between a 'normal' electrical drawing and a ladder diagram?
• How should you determine the ampacity of a 14 AWG copper conductor terminated in a location with 90°C insulation?
• In a 480V three-phase system, what are the typical line-to-line and line-to-neutral voltages for a wye configuration?
• Which statement best describes ground fault vs short circuit?
• All exposed, non-current carrying metal parts of an information technology system shall be grounded in accordance with NEC Article _____ or shall be double insulated.
• Which locations commonly require GFCI protection?
• Ventricular fibrillation is defined as?
• Which device interrupts a circuit when a fault current to earth is detected?
• What is a split-phase 120/240 V service, and how are the two hot legs arranged?
• What is a megohmmeter used for, and what is a typical acceptance test for insulation resistance?
• Which of the following best describes an advantage of crimp connectors for wire termination?
• What tool is used to verify grounding of a newly installed receptacle?
• Load is a part of an electrical circuit that uses electric current and voltage to perform some function; an example would be a lamp or electric motor.
• Arc-blast is described as a violent electrical condition that causes molten metal to be thrown through the air.
• Which task below must be completed before a switched duplex receptacle works properly?
• Define the dielectric strength of an insulating material and why it matters.
• Identify the electrical symbol for a motor starter, a contactor, and an overload relay.
• Electrical shock is the sudden stimulation of nerves and muscles caused by electricity flowing through the body.
• Which type of lamp is more efficient?
• Which type of luminaire is identified for direct contact with combustible material?
• Arc-flash is defined as a dangerous condition associated with the possible release of energy caused by an electric arc.
• Another name given to finish wiring is _____ out.
• A switched receptacle requires ____ conductors to work properly?
• Current is the intensity of electron flow in a conductor.
• Which of the following is considered an insulator?
• In a four-location lighting control setup, which configuration of switches is used?
• What is another term for a light fixture used in building electrical terminology?
• Distinguish between grounding and bonding. Which statement is correct?
• How long are ground rods?
• The symbol 'S' in electrical diagrams represents which type of switch?
• OSHA requires voluntary compliance and employers may comply if they want to.
• According to code, what size copper conductors feed a GFCI receptacle in a bathroom?
• When wiring a 120/240 V receptacle, how many hots, neutrals, and grounding conductors are typically connected, and what is the voltage to each hot relative to neutral?
• Which is the correct unit to measure electrical resistance?
• When performing a voltage regulator check on a transformer, which readings are most important?
• Who publishes the NEC?
• How would you approach troubleshooting a circuit in which a receptacle is dead but other devices on the same circuit operate?
• Current is defined as the intensity of electron flow in a conductor.
• What is the multiplier for a 30 degree offset?
• Which two factors are essential to determine lighting requirements?
• What does ampacity mean in relation to a conductor?
• What is the multiplier for a 10 degree offset?
• In a motor control circuit, which component provides overload protection for the motor?
• Briefly describe how a voltage regulator maintains output voltage under varying load.
• What is the unit of the electrical resistance?
• SDS stands for Safety Data Sheet. What information does an SDS provide?
• In a ladder diagram, what does a rung represent?
• Which conductor can be connected to a lug that is listed for CU only?
• Which device interrupts a circuit when a leakage to earth is detected?
• What is the purpose of a grounding electrode conductor (GEC), and to what is it connected?
• What does the acronym OCPD stand for in electrical protection?
• What is the role of an overload relay in a motor control circuit?
• If a three-way switch lighting circuit works from one switch and not the other, the most probable cause is
• Which of the following is commonly included in Personal Protective Equipment (PPE)?
• How many conductors are required for a switched receptacle to work properly?
• Two resistors 30 Ω and 60 Ω are connected in series across a 120 V source. What is the total resistance, the current, and the voltage drop across each resistor?
• When reading a schematic symbol for a contactor, what does a dashed line typically indicate?
• Name two common wire termination methods for conductors and one advantage of each.
• Which organization publishes the National Electrical Code?
• A four-way switch is represented by which symbol?
• What term describes the opposition to current flow in a conductor?
• For a 60 Hz system, calculate the inductive reactance of a coil with 0.2 H inductance.
• In a simple 120/240 V service, how many conductors are required for a 120/240 V 3-wire system and what are their roles?
• A normally opened limit switch is open when not actuated. Which state best describes this?
• What is the primary difference between a wiring diagram and a schematic diagram?
• Which numerical value represents the multiplier used with a 45 degree offset?
• In electrical terms, voltage is defined as which of the following statements?
• What is the typical effect of higher ambient temperature on the ampacity of a conductor installed in a conduit?
• The NEC table used to determine conductor ampacity is:
• What is the multiplier for a 45 degree offset?
• What is the primary purpose of a circuit breaker in electrical systems?
• In a split receptacle, how is the outlet typically configured?
• Hazard is a potential source of danger.
• What voltage results on the secondary of a transformer with a 400 turns primary and 200 turns in the secondary when 240 volts are applied to the primary?
• A continuous load of 30 A requires a minimum OCPD size based on the 125% rule.
• What is the function of a bonding jumper in a service panel?
• When calculating lighting requirements for a room, which two primary factors are typically considered?
• In NEC terminology, which word indicates that a rule must be followed?
• For ceiling fans, the weight threshold that requires independent support from the outlet box is:
• When mounted on a wall, the top of a smoke detector must be within how many inches of the ceiling?
• In the four-band resistor color code, what do the first two bands represent?
• In an electrical circuit, which component produces the voltage and current required by the circuit?
• Which device protects 120-volt bedroom circuits in new dwellings?
• The unit of measure for electrical resistance is the
• What is the primary purpose of a clamp-on meter, and what does it measure?
• Why is proper box fill important, and what could happen if it is undersized?
• A transformer with turns ratio Np:Ns = 240:120. If the primary is supplied with 240 V, what is the secondary voltage? If the secondary current rating is 2 A, what is the primary current (ideal transformer)?
• Which NEC article pertains to grounding and bonding?
• What is the purpose of a grounding conductor?
• Fires near electrical equipment are classified as Class C fires. Which option correctly lists classes?
• The NEC gives minimum safety standards for electrical work and is not a how-to manual. Which statement is true?
• To control a load from four locations, the switches needed are
• In a multi-hot circuit, what color is commonly used to indicate a second hot conductor besides black?
• To wire a structure with receptacles at $35 per outlet, what is the cost for a 24- foot by 24- foot building with receptacles placed every 12 feet?
• What is the purpose of a pull box in conduit runs?
• Which of the following is an example of bonding?
• Before installing a switched duplex receptacle, which modification must be made?
• Double insulated refers to an electrical power tool that is constructed so the case is isolated from electrical energy and made of nonconductive material.
• Which option best describes a commonly used connector for joining two #14 AWG conductors?
• Among common lamp types, which is generally more efficient for general lighting needs?
• A 24 V DC source connected to a 6 Ω resistor. Calculate current and power dissipated.
• Which units are used to express lighting level in spaces?
• Which instrument is used to measure insulation resistance?
• During troubleshooting fluorescent and HID lighting fixtures, which component is replaced first?
• In residential applications, every means of egress shall have a/an ______ outlet.
• Which device is commonly used to automatically turn lighting on when a room is occupied?
• What device monitors current balance and trips on imbalance to protect people from shock?
• In switch terminology, a normally closed contact means what when the actuating condition is not present?
• How does a motor starter differ from a simple contactor?
• Which step comes immediately after applying lockout in a lockout/tagout procedure?
• What size copper conductor feeds a bathroom GFCI receptacle according to code?
• What is the function of a GFCI and where is it required in wet locations?
• In box fill calculations, how many counts do grounding conductors contribute?
• OSHA's compliance framework as described in the material is:
• Insulator is a material that does not allow electrical current to flow through it; examples rubber, plastic, glass.
• Which code article pertains to definitions?
• What is the metric trade size for 1/2 inch EMT?
• Why is it essential to follow NEC ampacity tables when selecting conductors for a branch circuit?
• When installing a NM connector, tighten it until
• In an AC circuit, impedance is composed of which elements?
• What is the primary purpose of tagging in lockout/tagout procedures?
• Explain the concept of a 'feed-through' node in a simple wiring diagram.
• Two resistors 8 Ω and 12 Ω in parallel across 120 V. What is the equivalent resistance and the total current?
• If a 20 square meter room needs 400 lux, what is the approximate total lumen requirement?
• In an electrical circuit, which part uses electric energy to perform its function, such as lighting or motion?
• What is the term used when installing smoke detectors, so when one goes off they all go off?
• The slowest Internet connection is a ________ connection.
• A 120 V supply feeds a load with a power factor of 0.8 lagging and a current of 10 A. Determine the real power, reactive power, and apparent power.
• In a 480Y/277 V system, what is the voltage between line A and line B?
• What information does the Safety Data Sheet (SDS) provide?
• If an electrician's hands are wet while operating a 120-volt corded drill, which statement is true?
• PPE stands for which category of equipment used to protect workers?
• In a 2-gang box containing a 2-wire NM cable and a 3-wire cable with a ground, how should conductors be counted for box fill?
• GFCI is a device that protects people from dangerous levels of electrical current by measuring the current difference between two conductors; it trips when the difference is 6 milliamperes or higher.
• In a standard 120 V outlet wired with NM cable, which colors correspond to hot, neutral, and ground?
• The resistance–current relationship states that higher resistance results in what for current?
• Define and give the formula for capacitive reactance.
• The relation between resistance and current is:
• Currently DSL service is offered by
• Define voltage drop and explain why it matters in branch circuits.
• In NEC box fill calculations, how are internal clamps treated?
• When supplying voltage to a switched receptacle, the hot and switched voltage must be supplied from
• Is the grounding prong on a three-prong plug optional and may be removed?
• What is the purpose of the NEC?
• When stripping NM cable in a metal box, at least____ of sheath should be extended into the box.
• In a three-way switch circuit, how many switches are involved and what is the typical purpose?
• What is the take up for 1 inch EMT on a hand bender?
• Which material does not allow electrical current to flow through it?
• Safety eyeglasses and goggles should only be worn when working on live circuits or equipment. Which statement about safety eyewear is consistent with the material?
• Lockout/Tagout (LOTO) is a safety procedure designed to prevent injuries by isolating energy sources during maintenance. What is its primary purpose?
• Which term is defined as a material that allows electrical current to flow easily, with examples such as copper, aluminum, and silver?
• What must be installed within 25 feet of HVAC equipment located outdoors?
• Which scaffolding practice is NOT recommended?
• Which term describes a potential source of danger in an electrical system?
• Which conductor size is typically appropriate for an appliance requiring 8 A at 120 V?
• Which statement about polarized plugs is true?
• Which device is typically used to protect a motor by interrupting current if the motor overheats?
• Which term describes an arrangement consisting of a power source, conductors, and a load?
• The minimum amount of free wire that must be left in a workbox is
• When selecting a circuit breaker for a branch circuit, which attributes are most important?
• Two resistors 20 Ω and 40 Ω in series across 120 V. What are the total resistance, current, and voltage drop across each resistor?
• A lug listed for CU only can be connected to which conductor?
• Which type of pliers is used to cut cables and conductors as well as to form, pull, and hold conductors?
• Bored holes through wood members must be kept a minimum distance from the nearest edge?
• The switch used to open and close a bell circuit is which type?
• If you exceed a device’s rated current, what is the likely consequence?
• What happens to current and impedance at resonance in a series RLC circuit?
• Ceiling fans heavier than what weight must be supported independently of the outlet box?
• Which of the following statements correctly describes a luminaire that can be in direct contact with combustible material?
• When interpreting a single-line diagram for a small motor control circuit, which steps are followed?
• In electrical terminology, what does NC stand for on a switch symbol?
• When splicing two #14 gauge wires, what type of splice should be used?
• What is the purpose of including start and stop controls in a motor control circuit?
• The current that can cause ventricular fibrillation is within which range?
• Aerial Lift is a mechanical device used to provide temporary access for people or equipment to locations above the ground; may also be known as 'cherry picker' or 'scissor lift'.
• The acronym AFCI stands for
• After installation, which test verifies insulation condition between conductors and earth?
• Distinguish between a single-pole and a double-pole switch and give a typical use for each.
• Which of the following is a recommended safety practice when using a digital multimeter on live circuits?
• If insulation temperature rating increases, what happens to conductor ampacity according to NEC tables?
• In a motor control diagram, which component is typically the load that the circuit controls?
• In conduit work, what is the primary function of a hand bender?
• Which statement about the NEC is true?
• Which describes a continuous load under NEC guidelines for sizing overcurrent protective devices, and what is the applicable factor?
• OSHA suggests that workers dealing with energized equipment should
• What is the maximum power rating for a device rated 15 A at 125 V?
• Fires in electrical equipment near motors, panelboards, and wiring are classified as which class?
• ARC fault circuit interrupters are required in which room?
• What type of clamp is used to connect ground wire to ground rod?
• When installing boxes, the gap around the box cannot be greater than ___ inch or the gap must be repaired?
• If the gap around an installed electrical box is greater than 1/8 inch, what must be done?
• In a lighting plan, what does an illuminance value expressed in foot-candles represent?
• Which connector is used for terminating RG-6 and RG-59 video systems?
• The Ohm is the unit used to measure which electrical property?
• The maximum weight of a fixture on an outlet is expressed in which unit?
• Which statement about the two hot legs in a 120/240 V service is false?
• The switch used to operate a bell circuit is typically:
• When a feed-through to a subpanel contains multiple current-carrying conductors in a raceway, what derating consideration applies?
• Which statement describes the Arc-flash hazard most accurately?
• Voltage is defined as?
• What does insulation resistance test acceptance values per spec mean?
• In a 120 V lighting circuit with a voltage drop of 8% along a long run, which of the following is NOT a way to reduce the drop?
• Two resistors 15 Ω and 25 Ω are connected in parallel across a 120 V source. Find the equivalent resistance, the total current, and the current through each branch.
• The symbol described as Split Receptacle represents which type of outlet?
• In a 3-branch parallel circuit, if branch currents are 4 A, 6 A, and 5 A, what is the total current?
• What is the take-up distance for 1/2 inch EMT when bending with a hand bender?
• When installing two ground rods, what is the minimum distance between them?
• Which device protects against arcing faults in electrical circuits?
• A bathroom is required to have a dedicated circuit of what amperage rating?
• Which law describes the relationship between current, voltage, and resistance in an electrical circuit?
• How does insulation temperature rating affect conductor ampacity and how is it determined?
• What does derating mean in the context of conductor sizing and protection?
• When wiring a three-way switch, which terminal is identified with a color different from the others?
• When smoke detectors are interconnected, what is the resulting behavior?
• Aerial Lift is also known as which of the following?
• Which unit is used to measure inductive reactance?
• What document establishes minimum safety rules for electricians performing electrical installations?
• State the basic NEC color code for conductors: hot, neutral, and ground.
• Name three common conduit types and one general use for each.
• What are typical arc flash PPE boundaries used in safety planning?
• What is the typical purpose of a UL-listed electrical box and its cover in installations?
• In arc flash safety planning, what terms describe energy exposure boundaries?
• Which step comes immediately after isolating energy sources in a lockout/tagout procedure?
• Which connector is a 75 ohm coaxial cable connector suitable for RG-6 and RG-59 cables and used for terminating video systems?
• In an AC circuit, how does impedance affect current for a given voltage?
• If the impedance in an AC circuit is lowered while voltage is kept constant, what happens to current?
• What is the multiplier for a 15 degree offset in an electrical layout?
• How would you test a circuit for continuity using a digital multimeter, and what reading indicates continuity?
• Which description best characterizes the safety approach to energized equipment as recommended by OSHA?
• EMT stands for which term in electrical conduit terminology?
• Which statement best describes a split-phase system?
• In box fill calculations, what does the per-conductor volume depend on?
• Which of the following is NOT a derating factor for conductor ampacity?
• Which symbol is used to denote four-way switching in diagrams?
• What is the typical voltage between two legs of a 240 V split-phase system?
• In electrical terminology, a luminaire is best defined as what?
• What is a thermal overload in motor control, and how is it typically used?
• If receptacles are placed around a 24-by-24 building every 12 feet, and each receptacle costs $35, what is the total cost?
• Scaffolding is also referred to as staging and provides what function?
• Name two common types of electrical conduit used for outdoor or wet locations and a key property of each.
• Which term describes a connector commonly used for 75-ohm video and used to terminate coaxial cables?
• An AC circuit has a 60 Ω resistor in series with a 0.1 H inductor. The supply is 120 V rms at 60 Hz. Calculate the impedance magnitude, current, and phase angle.
• What is the difference between a GFCI and an AFCI device?
• A transformer has 400 turns in the primary and 200 turns in the secondary. If 240 volts applied to the primary winding, the voltage measure of the secondary winding will be?
• In walls or ceilings of combustible material, box set back must be ______ inches with the finished surface.
• What is the take up for 3/4 inch EMT on a hand bender?
• How would you determine box fill for a metal box containing two switches and three conductors terminating inside?
• Explain the behavior of a normally closed contact when energized.
• What is the role of the equipment grounding conductor in a typical electrical system?
• Which method correctly calculates NEC box fill capacity for a metal box?
• A luminaire requires 3200 lumens in a workspace of 40 ft by 50 ft. What is the approximate illuminance in foot-candles?
• How many terminals does a standard three-way switch have (excluding ground)?
• How many current carrying conductors are sealed between two three-way switches?
• When installing boxes, the gap around the box cannot be greater than what inch?
• A load with a power factor of 0.8 lagging. The angle between voltage and current is approximately what?
• Which statement best describes Ohm's law in simple terms?
• How does a GFCI differ in how it protects a person versus a traditional breaker?
• When a light fixture is to be placed in a ceiling filled with insulation, what type of light needs to be used?
• All 120-volt, single phase, 15- and 20- ampere branch circuits supplying outlets installed in dwelling unit bedrooms shall be protected by a/an
• What does the term ampacity refer to, and how would ambient temperature affect it?
• A transformer with turns ratio Np:Ns = 100:50. If the primary is supplied with 200 V, what is the secondary voltage? If the rated secondary current is 4 A, what is the primary current (ideal)?
• If a circuit breaker trips immediately when turned on, what is the first issue you should inspect?
• Which code article addresses grounding and bonding?
• A dotted line between components on a three-phase schematic usually indicates?
• In a ladder diagram, what does a normally open contact represent?
• When sizing a feeder to a subpanel, how should three conductors in the feed-through be evaluated?
• In a 480Y/277 V system, what is the line-to-neutral voltage?